ACETOPHENONE The various reactions, known as the Friedel-Crafts reactions, arc effected by means of anhydrous aluminium chloride. The aluminium chloride, being- very hygroscopic, cannot be kept long, even in a stoppered bottle, without undergoing- gradual decomposition. As the success of the reaction depends entirely on the quality of the chloride, it should be either freshly pro- cured, from a reliable firm or resublimed from a retort. It may also be prepared on a small scale by passing dry hydrochloric acid over heated aluminium foil or filings, but the operation is troublesome and scarcely repays the time spent. Attach a round flask (500 c.c.) to an upright condenser, and bring into it the aluminium chloride, which should be well powdered, and immediately cover it with the benzene. Place the flask in ice- water, and add the acetyl chloride drop by drop from a tap-funnel, which is pushed into the top of the condenser.* A vigorous effervescence occurs, and hydrochloric acid is evolved. The contents of the flask are converted into a brown, viscid mass, which, after standing an hour, is stirred up and shaken into a beaker containing ice and water (250 c.c.). The mass decom- poses with evolution of heat, and a dark oil separates on the surface. The liquid is poured into a separating-funnel and a little benxene added. The aqueous portion is drawn off, and the benzene layer shaken up with dilute caustic soda and then with water. The benzene solution is finally separated, de- hydrated over calcium chloride, filtered, and distilled. The benxene first passes over. The thermometer then rises quickly to 195°. The receiver is now changed, the water run out of the condenser, and the distillate, which boils at 195—200°, collected separately. It forms a pale yellow oil with a characteristic sweet smell, and solidifies completely on standing. Yield, 20—25 grams. C(;H(J + CH3COCl = CUH6.CO.CH3 4- HCL Properties.—Colourless plates ; m. p. 20° ; b. p. 202° ; insoluble in water. Reacfi<ws*—i. Acetophenoneoxime.—Mix together 5 grams of hydroxylamine hydrochloride dissolved in 10 c.c. of water, 8 grams of acetophenone, and 3 grams of caustic soda dissolved in a very little water. Add spirit until, on warming, the solution becomes clear, and boil it on the water-bath 2—3 hours.